Concept:Height and weight are quantitative traits that show a wide range of intermediate values in a population.Explanation:When students are measured for height and weight, the values do not fall into just a few distinct categories.Instead, they spread smoothly from very short to very tall and from very light to very heavy.This gradual spread with many intermediate steps is known as continuous variation.Such traits are usually controlled by multiple genes and are also affected by environmental factors like nutrition.Answer:B. continuous variation